OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-4,-4,12,-12,4,12,-22,12,4,-12,12,-4,-4,4,-1).
FORMULA
G.f.: P_4(x) / ((1-x)^2*(1-x^2)^2*(1-x^3)^2*(1-x^4)^2), with P_4(1) = 7!, where P_4(x) = (1+3*x+28*x^2+94*x^3+240*x^4+440*x^5+679*x^6+839*x^7+ 887*x^8+757*x^9+550*x^10+314*x^11+148*x^12+48*x^13+11*x^14+x^15).
MATHEMATICA
CoefficientList[Series[(1 + 3*x + 28*x^2 + 94*x^3 + 240*x^4 + 440*x^5 + 679*x^6 + 839*x^7 + 887*x^8 + 757*x^9 + 550*x^10 + 314*x^11 + 148*x^12 + 48*x^13 + 11*x^14 + x^15)/((1 - x)^2*(1 - x^2)^2*(1 - x^3)^2*(1 - x^4)^2), {x, 0, 50}], x] (* G. C. Greubel, Oct 16 2017 *)
LinearRecurrence[{4, -4, -4, 12, -12, 4, 12, -22, 12, 4, -12, 12, -4, -4, 4, -1}, {1, 5, 39, 175, 618, 1764, 4420, 9900, 20439, 39325, 71603, 124215, 207076, 333200, 520272, 790704}, 40] (* Harvey P. Dale, Feb 04 2023 *)
PROG
(PARI) {a(n)=polcoeff(truncate(Ser([1, 3, 28, 94, 240, 440, 679, 839, 887, 757, 550, 314, 148, 48, 11, 1]))/ ((1-x)^2*(1-x^2)^2*(1-x^3)^2*(1-x^4)^2 +x*O(x^n)), n)}
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul D. Hanna, Oct 03 2006
STATUS
approved